This invention intends to enhance luminance of electrode-less lamp by improving lamp-cooling efficiency that shines in a microwave electromagnetic field and to provide with electrode-less lamp equipment with the lamp.
This kind of electrode-less lamp equipment by former arts is known for example such as those in Japan Patent Bulletins Tokukai-Hei 2-117003 and Jitsukai-Hei 4-131853. FIGS. 7 and 8 show an example of electrode-less lamp equipment by current arts. FIG. 7(a) shows a longitudinally cut cross-section view and FIG. 7(b) shows a partially cut plane view from the bottom. FIG. 8 shows a vertical section view that shows the coupling of a microwave-generating source, a waveguide, and a microwave chamber.
This electrode-less lamp equipment is furnished with an electrode-less lamp 1 of a glass tube made from crystal in which light-emission material such as mercury is enclosed. The electrode-less lamp 1 is fixed in a microwave chamber 2. The microwave chamber 2 consists of a box-shaped metal chamber wall 3 with an open port at the bottom and a mesh 4 at the open port of the chamber wall 3.
A light-beam-collection mirror 8 is settled in the microwave chamber 2 by which the light beam emitted from the electrode-less lamp 1 is collected and is guided toward the open port of the microwave chamber 2. The light-beam-collection mirror 8 consists of a concave mirror of half-split tube with a side section of half ellipse. The electrode-less lamp 1 and the light-beam-collection mirror 8 are arranged and fixed on the chamber wall 3 so that the light-beam-collection mirror 8 is positioned at the focus point of the ellipse.
The bottom end of the waveguide 6 is fixed at the exterior surface of the upper end of the microwave chamber 2 and the microwave generating source 5 consisting of two magnetrons is fixed at the upper end of the waveguide 6. On the opposite side of the waveguide 6, the lower end of which extends an antenna 7 into the microwave chamber 2. The antenna 7 is arranged between the electrode-less lamp and the light-beam collection mirror 8, in parallel with the light-beam collection mirror 8. One end of the antenna 7 is connected to the chamber wall 3 and the other end is connected a coaxial waveguide converter (not present in the Figures) in the waveguide 6 through antenna through-holes 10 and 11. For convenience of notation, FIG. 7(b) omitted the antenna through-holes 10 and 11. Furthermore for simplicity, in FIG. 7(a), at only one side are numbered the elements of the symmetric devices such as waveguide 6.
A blower 9 is equipped with at the upper side of the waveguide 6. The waveguide 6 and the microwave chamber 2 have ventilation holes 12 and 13 respectively at the upper ends. Around the bottom of the concave of the light-beam-collection mirror 8 that is at the opposite end against the open end of the light-beam-collection mirror 8, are formed ventilation holes 14. The components above described are settled in a case 16 that is uniformly configured with the chamber wall 3. In the electrode-less lamp equipment above described, the microwave generated with the microwave-generating source 5 is induced to the microwave chamber 2 through waveguide 6 and antenna 7 and is reflected in the microwave chamber 2 and excites the enclosed gas such as mercury and produces plasma in the electrode-less lamp, which results in emission of light including ultraviolet. The light beam is collected with the beam-collection mirror 8 and focuses on the beam-collection surface FP that is another focus point of the ellipse. The airflow sent by the blower 9 follows the arrow in FIG. 8 through the ventilation holes 12, 13, and 14 then cools the electrode-less lamp 1.
However, in the electrode-less lamp equipment by the former arts, a restricted durability of the mirror surface against heat and an optical disadvantage that the beam-collection mirror 8 needs high magnification if the distance between the focus point and the ellipse bottom is short prevented closer setting of the beam-collection mirror 8 to the electrode-less lamp 1. Accordingly, the airflow emitted through the ventilation hole 14 on the beam-collection mirror 8 slowed down around the electrode-less lamp 1, which reduced the cooling efficiency and resulted in low input density to the lamp and low luminance. This invention intends to solve the problems above described and to raise lamp luminance by improving the lamp cooling efficiency and to provide with electrode-less lamp equipment.
Electrode-less lamp equipment in this invention is comprising ventilation nozzles for airflow that cool the electrode-less lamp in the electrode-less lamp equipment consisting of a microwave-generating source, a microwave chamber receiving the microwave from the microwave-generating source, a bar-shaped electrode-less lamp in the microwave chamber, and a half-cut cylinder-shaped concave mirror that collects the light beam from the lamp. This nozzle may be set closer to the electrode-less lamp than the ventilation holes of the equipment by the former arts might be set. The close setting of the nozzle improved lamp-cooling efficiency and enabled higher input density resulting in higher luminance or in less airflow if the luminance is not increased.